package com.dc.platform;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URLEncoder;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class DownLoadServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
			//得到要下载的文件名
			String fileName = request.getParameter("filename");
			fileName = new String(fileName.getBytes("iso8859-1"),"UTF-8");
			//上传的文件都是保存在/WEB-INF/upload目录下的子目录当中
			String fileSaveRootPath=this.getServletContext().getRealPath("/WEB-INF/sql");
			//得到要下载的文件
			File file = new File(fileSaveRootPath + "\\" + fileName);
			//如果文件不存在
			if(!file.exists()){
			request.setAttribute("message", "您要下载的资源到火星去了！！");
			request.getRequestDispatcher("/message.jsp").forward(request, response);
  			return;
			}
			//设置响应头，控制浏览器下载该文件
			response.setHeader("content-disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
			//读取要下载的文件，保存到文件输入流
			FileInputStream in = new FileInputStream(fileSaveRootPath + "\\" + fileName);
			//创建输出流
			OutputStream out = response.getOutputStream();
			//创建缓冲区
			byte buffer[] = new byte[1024];
			int len = 0;
			//循环将输入流中的内容读取到缓冲区当中
			while((len=in.read(buffer))>0){
			//输出缓冲区的内容到浏览器，实现文件下载
			out.write(buffer, 0, len);
			}
			//关闭文件输入流
			in.close();
			//关闭输出流
			out.close();
	}
	

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

	}


}
